The present invention relates to an information carrier obtained by supporting on a substrate at least one fitting for, for example, storing, displaying or processing information, and a process for producing the same. In particular, it relates to a non-contact type information carrier obtained by the use of an IC chip and a coil and a process for producing the same.
Various information carriers have been proposed which are obtained by supporting on a substrate an IC chip and a part for supplying a power source and/or transmitting information signals, store information, and give information to a reader•writer or receive information therefrom. Such information carriers are used for, for example, storing personal information on deposits, insurances, commutation tickets, licences, health, identification, etc., information on product management in factories, and information on commodity management in the commodity distribution field, or the employment of the information carriers for such purposes is investigated.
FIG. 20 and FIG. 21 are diagrams showing an example of such an information carrier which has been known: FIG. 20 is a partially sectioned plan view of the information carrier, and FIG. 21 a sectional view taken along the line II—II of FIG. 20. In these drawings, the symbol 100 shows an IC chip; the symbol 101 a coil connected to the IC chip 100; the symbol 102 a substrate supporting the IC chip 100 and the coil 101; the symbol 103 a resin constituting the substrate 102; the symbol 104 a reinforcer for the resin 103; and the symbols 105 and 106 cover sheets attached to the right side and reverse side, respectively, of the substrate 102 through bonding layers 110, respectively.
As is clear from these drawings, in this example of the information carrier, the IC chip 100 and the coil 101 are placed in a cut-out hole 104a made in the reinforcer 104, and the space in the cut-out hole 104a is filled with the resin 103, which is infiltrated into the reinforcer 104, whereby the substrate 102 is formed. Since this example of the information carrier thus comprises the reinforcer 104 having the cut-out hole 104a, and the IC chip 100 and coil 101 placed in the cut-out hole 104a, a position in the substrate 102 at which the coil 101 is set can be accurately controlled by adjusting the size of the cut-out hole 104a to a suitable size for the coil 101, so that the efficient receipt of electric power from an external equipment and the efficient transmission of signals from or to the external equipment are possible.
The above well-known example of the information carrier, however, involves the following problem: since the IC chip 100 and the coil 101 are placed in the cut-out hole 104a made in the reinforcer 104 and the resin 103 inside and outside the cut-out hole 104a is cured, the strength inside the cut-out hole 104a having no reinforcer 104 is low, so that when the information carrier receives an irregular external force such as flexture, stress is concentrated within the cut-out hole 104a, resulting in easy cracking of the substrate 102.
Said information carrier also involves the following problem: after accurately setting the IC chip 100 and the coil 101 in the reinforcer 104 having the required cut-out hole 104a, filling of the cut-out hole 104a with the resin, impregnation of the reinforcer 104 with the resin, and curing of the resin have to be carried out, so that a complicated production process is required, resulting in difficult production of an inexpensive information carrier. Particularly when various information carriers are produced on the same production line, reinforcers 104 different in the size of the cut-out hole 104a have to be prepared depending on the sizes of the IC chip 100 and the coil 101 which are to be placed in the cut-out hole 104a, so that a more complicated production process is required, resulting in a high production cost of the information carriers.
In addition, in the above well-known example of the information carrier, the reinforcer 104 is made of, for example, woven fabric obtained by plain weave of glass fiber, so that when the cut-out hole 104a is made by cutting the reinforcer 104, glass fibers are frayed and stuck out of the cut surface to cause the following phenomenon: as shown in FIG. 22, the frayed glass fibers 107 jut out inside the cut-out hole 104a or extend above or below the reinforcer 104.
When the frayed glass fibers 107 thus jut out inside the cut-out hole 104a, the following disadvantage is brought about: as shown in FIG. 23, which is a sectioned plan view taken along the line C—C of FIG. 22, the thickness of a portion where the IC chip 100 and/or the coil 101 overlaps with the glass fibers 107 exceeds the thickness of the substrate 102, so that the surface flatness of the substrate 102 and hence that of the cover sheets 105 and 106 are deteriorated. When the frayed glass fibers 107 extend above or below the reinforcer 104, the thickness of such a portion is larger than that of the other portion of the substrate 102, so that the flatness of the cover sheets 105 and 106 is deteriorated. When the flatness of the cover sheets 105 and 106 is deteriorated, the beautiful appearance and the ease of handling are deteriorated, resulting in a decreased commercial value. Furthermore, when the information carrier is such that, for example, a photograph of owner's face is printed on the surface of the cover sheet 105 or 106 after the production of the information carrier, the information carrier is disadvantageous in that the photograph of the face cannot be clearly printed.
Since the woven fabric obtained by plain weave of glass fiber is hardly compressible in the direction of the thickness, pressing of the substrate 102 cannot remove the thickness nonuniformity of the substrate 102 and moreover tends to destroy the IC chip 100 and the coil 101. The above-mentioned disadvantage can be removed by stopping the fraying, for example, by hardening and fixing the glass fibers 107 frayed and stuck out of the cut surface with a resin before inserting the IC chip 100 and the coil 101 into the cut-out hole 104a, but a production process of the information carrier becomes complicated as much, resulting in an increased production cost of the information carrier. Therefore, this method is not preferable.
In addition, since the above well-known example of the information carrier has a structure in which the cover sheets 105 and 106 are attached to the right side and reverse side, respectively, of the substrate 102 through the bonding layers 110, respectively, it is difficult to produce an information carrier with a good surface condition in high yield, so that the information carrier tends to cost a great deal. Moreover, since the bonding layer of about 0.1 mm thickness is necessary on each side, it is difficult to thin the information carrier. Depending on a material for the substrate 102 and a material for the cover sheets 105 and 106, the following problem is also caused: no high bond strength can be attained, so that the cover sheets 105 and 106 are peeled from the substrate 102 during use or shaping of the information carrier. For example, when a poly(ethylene terephthalate) (hereinafter abbreviated as “PET”) is used as the cover sheets 105 and 106, peeling tends to be caused between the bonding layer 110 and each of the cover sheets 105 and 106, resulting in an insufficient utility of the information carrier.
Moreover, in the above well-known example of the information carrier, polyvinyl chloride, which is good in printing property and adhesion property, is typically used as the cover sheets 105 and 106. When polyvinyl chloride is burnt, chlorine gas is generated. Thus, the information carrier using polyvinyl chloride may deteriorate earth environment. Therefore, it is intensively desired to develop an information carrier free of such an environmental problem. If PET or PEN, which does not generate chlorine gas when burnt, is used as the cover sheets 105 and 106, an information carrier free of the environmental problem can be obtained. However, PET and PEN are poor in adhesion property as described above so that PET or PEN per se cannot be used as the cover sheets. Furthermore, PET and PEN are poor in printing property. Thus, it is difficult to print beautiful images on an information carrier comprising cover sheets 105 and 106 composed of PET or PEN.